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arXiv · 1507.03483

Quantum-State Purity of Heralded Single Photons Produced from Frequency-Anti-Correlated Biphotons

Shengwang Du
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Abstract

We analyze the quantum-state purity of heralded single photons produced from frequency-anti-correlated biphotons. We find that the quantum-state purity in time-frequency domain depends strongly on the response time uncertainty of the trigger-photon detector that heralds the generation of its paired photon. If the trigger response time is much shorter than the two-photon coherence time, the time-frequency quantum-state purity of heralded single photons approaches unity and the heralded single photon is in a nearly pure state. If the trigger response time is much longer than the two-photon coherence time, the heralded photon is then projected onto a mixed state. Making use of the time-frequency entanglement, heralded single photons with a well-defined temporal wave function or a frequency superposition state can be produced and engineered. This time-frequency entanglement allows for shaping heralded single photons through nonlocal spectral modulation.

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Shengwang Du. 2015-09-15. Quantum-State Purity of Heralded Single Photons Produced from Frequency-Anti-Correlated Biphotons. https://doi.org/10.1103/physreva.92.043836

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